Network reselection by a wireless communication device based on signal-to-noise ratio

Abstract

A method for network reselection by a wireless communication device is provided. The wireless communication device can have an established connection to a first network. The method can include measuring a signal strength and a signal-to-noise ratio of the first network. The method can further include determining that the signal strength satisfies a signal strength threshold. The method can additionally include comparing the signal-to-noise ratio to a signal-to-noise ratio threshold. The method can also include disconnecting from the first network and reselecting to a second network in an instance in which the signal-to-noise ratio does not satisfy the signal-to-noise ratio threshold even though the signal strength satisfies the signal strength threshold.

What is claimed is: 
     
       1. A method for network reselection by a wireless communication device, the method comprising:
 measuring a reference signal receive power (RSRP) and a reference signal signal-to-interference-and-noise ratio (RS-SINR) of a first network, wherein the wireless communication device has an established connection to the first network, and wherein the first network operates in accordance with a Long Term Evolution (LTE) wireless communication protocol; 
 determining that the RSRP satisfies an RSRP threshold; 
 comparing the RS-SINR to a signal-to-interference-and-noise ratio (SINR) threshold; and 
 disconnecting from the first network and reselecting to a legacy network having a circuit switched domain when the RS-SINR does not satisfy the SINR threshold and the RSRP satisfies the RSRP threshold. 
 
     
     
       2. The method of  claim 1 , wherein the RSRP threshold is defined by the first network, and wherein the SINR threshold is defined by the wireless communication device. 
     
     
       3. The method of  claim 1 , wherein the SINR threshold is defined as an SINR sufficient to enable successful decoding of a paging message received from the first network. 
     
     
       4. The method of  claim 1 , wherein the SINR threshold is determined based at least in part on historical data of one or more paging messages previously missed by the wireless communication device. 
     
     
       5. The method of  claim 4 , wherein the SINR threshold is determined further based on a location of the wireless communication device. 
     
     
       6. The method of  claim 1 , further comprising:
 measuring a channel quality of the legacy network prior to reselecting to the legacy network; and 
 wherein reselecting to the legacy network comprises reselecting to the legacy network when the channel quality of the legacy network satisfies a channel quality threshold, and wherein the method further comprises remaining on the first network when the channel quality of the legacy network does not satisfy the channel quality threshold. 
 
     
     
       7. The method of  claim 1 , wherein the LTE wireless communication protocol is one of a version of a Third Generation Partnership Project (3GPP) LTE or LTE-Advanced (LTE-A) wireless communication protocol, and wherein the legacy network is one of a Wideband Code Division Multiple Access (WCDMA) network, a Universal Mobile Telecommunications System (UMTS) network, a Global System for Mobile Communications (GSM) network, or a network operating in accordance with a wireless communication protocol of the Third Generation Partnership Project 2 (3GPP2). 
     
     
       8. A method for network reselection by a wireless communication device, the method comprising:
 measuring a signal strength and a signal-to-noise ratio of a first network, wherein the wireless communication device has an established connection to the first network; 
 determining that the signal strength satisfies a signal strength threshold; 
 comparing the signal-to-noise ratio to a signal-to-noise ratio threshold; and 
 disconnecting from the first network and reselecting to a second network when the signal-to-noise ratio does not satisfy the signal-to-noise ratio threshold and the signal strength satisfies the signal strength threshold. 
 
     
     
       9. The method of  claim 8 , wherein measuring the signal-to-noise ratio comprises measuring a signal-to-interference-and-noise ratio (SINR) of the first network, and wherein comparing the signal-to-noise ratio to the signal-to-noise ratio threshold comprises comparing the measured SINR to an SINR threshold. 
     
     
       10. The method of  claim 9 , wherein measuring the SINR of the first network comprises measuring a reference signal SINR (RS-SINR) of the first network. 
     
     
       11. The method of  claim 8 , wherein measuring the signal strength of the first network comprises measuring a reference signal receive power (RSRP) level of the first network, and wherein the signal strength threshold comprises an RSRP threshold. 
     
     
       12. The method of  claim 8 , wherein the signal strength threshold is defined by the first network, and wherein the signal-to-noise ratio threshold is defined by the wireless communication device. 
     
     
       13. The method of  claim 8 , wherein the signal-to-noise ratio threshold is defined as a signal-to-noise ratio sufficient to enable successful decoding of a paging message to establish a voice connection. 
     
     
       14. The method of  claim 8 , further comprising:
 measuring a channel quality of the second network prior to reselecting to the second network; and 
 wherein reselecting to the second network comprises reselecting to the second network only in an instance in which the channel quality of the second network satisfies a channel quality threshold, and wherein the method comprises remaining on the first network in an instance in which the channel quality of the second network does not satisfy the channel quality threshold. 
 
     
     
       15. A wireless communication device comprising:
 wireless circuitry configured to transmit data to and receive data from a first network and a second network; and 
 processing circuitry coupled to the wireless circuitry, the processing circuitry configured to control the wireless communication device to at least:
 establish a connection to the first network; 
 measure a signal strength and a signal-to-noise ratio of the first network; 
 determine that the signal strength satisfies a signal strength threshold; 
 compare the signal-to-noise ratio to a signal-to-noise ratio threshold; and 
 disconnect from the first network and reselect to the second network when the signal-to-noise ratio does not satisfy the signal-to-noise ratio threshold and the signal strength satisfies the signal strength threshold. 
 
 
     
     
       16. The wireless communication device of  claim 15 , wherein the processing circuitry is configured to control the wireless communication device to:
 measure the signal strength at least in part by measuring a reference signal receive power (RSRP) level of the first network, and wherein the signal strength threshold comprises an RSRP threshold; and 
 measure the signal-to-noise ratio at least in part by measuring a reference signal-signal-to-interference-and-noise ratio (RS-SINR) of the first network, and wherein the signal-to-noise ratio threshold comprises a signal-to-interference-and-noise ratio (SINR) threshold. 
 
     
     
       17. The wireless communication device of  claim 15 , wherein the signal strength threshold is defined by the first network, and wherein the signal-to-noise ratio threshold is defined by the wireless communication device. 
     
     
       18. The wireless communication device of  claim 17 , wherein the processing circuitry is further configured to control the wireless communication device to determine the signal-to-noise ratio threshold based at least in part on historical data for reception and decoding of one or more paging messages by the wireless communication device. 
     
     
       19. The wireless communication device of  claim 18 , wherein the signal-to-noise ratio threshold is defined as a signal-to-noise ratio sufficient to enable successful decoding of a signaling message that specifies a page for a voice connection. 
     
     
       20. The wireless communication device of  claim 18 , wherein the processing circuitry is further configured to control the wireless communication device to determine the signal-to-noise ratio threshold further based on a location of the wireless communication device.